The world’s widest tunnel drill advanced three feet Monday, pleasing Highway 99 officials after a month of delays.
By Mike Lindblom, September 23, 2013, Seattle Times
Tunnel machine Bertha finally woke up early Monday, and drilled three feet in its first hour.
The slow progress follows a month’s delay caused by a clog in the excavated muck, a dispute with longshore workers who were excluded from the Highway 99 tunnel project, and finally, some repairs and adjustments.
Neither the builders nor the state would provide a cost estimate Monday for the delay.
“At this point, we’ve been pleased with the builders’ attention to getting Bertha moving again and starting tunneling, and that it is able to move three feet,” said Todd Trepanier, Highway 99 program administrator for the state Department of Transportation.
Just before 5 a.m., the cylindrical 57-foot, 4-inch-diameter machine restarted, said Chris Dixon, project manager for the Seattle Tunnel Partners construction team.
Three feet later, the rotary grinding face was turned off, a normal step that allows crews in the rear to install 10 concrete segments that form the next tunnel ring.
The machine will push off each of the 1,450 rings, advancing the cutter by 6½ feet, until it stops again to build the succeeding ring.
On Monday afternoon, workers were still hoisting and fastening the ninth of 13 temporary rings, which must be braced by steel beams within the Sodo launch pit. Bertha has only made it halfway out of the pit since the July 30 startup, on its 1.7-mile odyssey north toward South Lake Union.
The machine should fully leave the pit late this week or early next week, Dixon said. After the drill escapes the pit, its hydraulic thrusters will push off permanent rings that are supported by the ground, and the job will move faster, Dixon said.
“We’re on our way,” he said.
The machine is still chewing through shallow soil mixed with concrete grout, then should reach better soil as it descends.
Last week Dixon said the companies believed the state should cover the millions of dollars in losses associated with delays.
He voiced a softer line Monday, saying staff for the state and Seattle Tunnel Partners “will be working together, looking at the impacts, seeing where the responsibility for any additional costs or any lost time falls underneath the contract, and we’ll work through that process, and proceed.”
The contract calls for cost disputes to be heard by an expert dispute-resolution board.
Gov. Jay Inslee announced last Tuesday that the International Longshore and Warehouse Union (ILWU) agreed to halt picketing at Terminal 46, and drilling could start in a few days. The tunnel team said Bertha would drill late last week.
However, the machine stayed idle through the weekend.
Dixon said the team could have drilled last week and decided instead to unclog foam injector nozzles that squirt conditioners into the soil, to make it slipperier and more consistent as it enters a conveyor system.
Some of the 86 nozzles were obstructed by soil, mixed with concrete, that hardened during the long shutdown, he said.
“Yeah, you can tunnel with only some of those working, but you can tunnel a lot more efficiently if they’re all working,” Dixon said.
Contractors still intend to drill through downtown and emerge at South Lake Union by November 2014 as originally scheduled. Last week, Dixon said one way to regain time is to drill around the clock, instead of the standard 20 hours a day, five days a week.
The $2 billion tunnel, funded by gas taxes and tolls, is supposed to open for traffic at the end of 2015.
Still unsettled is the labor dispute, in which longshore workers say that four loading jobs at Terminal 46, on two shifts per day, should be done by ILWU.
Dirt will be poured onto barges and shipped to a quarry near Port Townsend. The jobs have been assigned instead to building-trades workers. Another round of picketing is possible, but the ILWU says it’s pausing in hopes that Inslee’s involvement will bring a solution.
If digging stays on pace, Bertha will pass under the old Alaskan Way Viaduct in early 2014, causing a one or two-week traffic shutdown on the elevated highway.